The present invention relates to heat staking apparatus, and more particularly relates to an apparatus for heat staking parts together by heating and then forming plastic protrusions extending from one part into the other.
It is known to extend a plastic protrusion through an aperture, to heat the protrusion to a formable state, and then to form and cool the protrusion with a staking tool into an interlocking rivet-like headed fastener. In the automotive industry, heat staking apparatus are typically configured to assemble specific parts for a particular model of vehicles. It is desirable to run parts for related models that are similar but not identical on the same heat staking apparatus, however the similar parts often do not have exactly the same shape or pattern of protrusions, such that a particular heat staking apparatus cannot run both types of parts without considerable changeover. For this reason, usually a second heat staking apparatus is purchased. However, the additional machinery is expensive and also consumes precious floor space, and further requires additional maintenance. Additionally, plastic components may vary dimensionally from the designed shape, such that fine tuning of the relative locations of the heat staking tools is necessary, particularly during start-up.
Another problem is that the heater elements used to heat the hot air sometimes burn out. Usually, heater elements are positioned as close as possible to the point of use to provide maximum control over heated air, and to prevent loss of heat as the heated air moved from the heater to the protrusion to be heated. However, the area around the heat staking tools is often if not usually congested, particularly where there are multiple staking tools and/or multiple heaters. Further, maintenance people usually want to allow the heat staking apparatus to cool before removing the burned out heater elements, since the burned out heater elements must be unfastened or unbolted, and manipulated for removal. Unfortunately, this wastes production time.
Thus, a heat staking apparatus is desired solving the aforementioned problems.